<style type="text/css">
.container
{
    background-color: lightblue;
    /*border: 5px solid darkred;*/
    margin: 40px;
}
.rel_box
{
    background-color: lightcoral;
    border: 5px solid darkblue;
    height: 50px;
    position: relative;
    left: 50px;
    top: 10px;
    margin: 30px;
}
.flow_box
{
    background-color: lightcoral;
    border: 5px solid darkblue;
    height: 50px;
    margin: 30px;
}
</style>
<body>
    <div class="container">
        <div class="rel_box"></div>
        <div class="flow_box"></div>
    </div>
</body>
